Hydrocracking process

ABSTRACT

Hydrocracking catalysts comprise a Group VIB and/or non-noble metal Group VIII hydrogenation component in conjunction with an LZ-210 zeolite preferably of SiO 2  :Al 2  O 3  greater than 9.0, which zeolite has been hydrothermally treated and ammonium ion-exchanged. In a preferred embodiment, the zeolite is essentially free of rare earth metals, and most preferably, essentially free of all metals except the Group VIB or non-noble Group VIII.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.793,566 filed on Oct. 31, 1985, now U.S. Pat. No. 4,672,048, whichapplication is a continuation-in-part of (1) U.S. patent applicationSer. No. 695,850 filed Jan. 28, 1985, now U.S. Pat. No. 4,563,434 whichapplication is itself a division of U.S. patent application Ser. No.406,498 filed Aug. 9, 1982, now U.S. Pat. No. 4,517,073, which itself isa continuation-in-art of U.S. patent application Ser. No. 84,761 filedOct. 15, 1979, now U.S. Pat. No. 4,419,271, (2) U.S. patent applicationSer. No. 697,258 filed Feb. 1, 1985, now U.S. Pat. No. 4,576,711, whichapplication is itself a continuation of U.S. patent application Ser. No.406,498 filed Aug. 9, 1982, now U.S. Pat. No. 4,517,073, which itself isa continuation-in-part of U.S. patent application Ser. No. 84,761 filedOct. 15, 1979, now U.S. Pat. No. 4,419,271, (3) U.S. patent applicationSer. No. 746,186 filed June 18, 1985, and (4) U.S. patent applicationSer. No. 699,919 filed Feb. 8, 1985, now U.S. Pat. No. 4,610,973, whichitself is a continuation of U.S. patent application Ser. No. 531,924filed Sept. 13, 1983, now U.S. Pat. No. 4,517,074, which itself is adivision of U.S. patent application Ser. No. 84,761 filed Oct. 15, 1979,now U.S. Pat. No. 4,419,271. Both U.S. Pat. No. 4,517,073 and U.S. Pat.No. 4,419,271 are herein incorporated by reference in their entireties.

INTRODUCTION

The present invention relates to a hydrocracking catalyst and process,and particularly to a zeolite-containing hydrocracking catalyst and itsuse in hydrocracking gas oil feeds and the like into gasoline.

Hydrocracking is a well-known refining process wherein, in its typicalform, a relatively high boiling hydrocarbon feedstock is upgraded bycontact with a hydrocracking catalyst under conditions of elevatedtemperature and pressure and the presence of added hydrogen. Inhydrocracking, the catalyst promotes two reactions, first the crackingof a substantial proportion of the hydrocarbon components of thefeedstock and, second, the saturation of the resultant products byhydrogenation. The net result of hydrocracking is that the relativelyhigh boiling feed is converted into a lower boiling feed with a greaterproportion of components boiling in a desired range, e.g., C₄ + to 420°F. in the case of hydrocracking to produce gasoline, 300° to 700° F. inthe case of midbarrel hydrocracking to produce diesel fuel, and 300° to550° F. in the case of midbarrel hydrocracking to produce certainaviation fuels.

For the production of gasoline from gas oils and the like, the typicalhydrocracking catalyst is composed of one or more Group VIB or VIIImetals on a support comprising a zeolite having catalytic crackingactivity. One such zeolite is known as LZ-210, disclosed most fully inU.S. Pat. No. 4,503,023 issued to Breck et al. and assigned to UnionCarbide, which patent is herein incorporated by reference in itsentirety. LZ-210 is a distinctive form of zeolite in that, while itscrystal structure is similar to a Y zeolite, it has an unusually highframework silica-to-alumina ratio, above 6.0, due to the extraction ofaluminum from the Y zeolite structure by contact with an aqueoussolution of a fluorosilicate salt and incorporation of silicon from thesolution into the zeolite structure.

In a subsequent disclosure, in European Patent Application No.84104815.0, Publication No. 0124120, published Nov. 7, 1984 by Best etal., also assigned to Union Carbide, which patent application is hereinincorporated by reference in its entirety, two forms of LZ-210,denominated LZ-210-T and LZ-210-M, are disclosed, with the former beingthermally or hydrothermally treated form of LZ-210 and the latter aLZ-210 zeolite exchanged with a multivalent metal, preferably a rareearth metal or mixture of rare earth metals. Both LZ-210-T and LZ-210-Mhave a silica-to-alumina ratio between 6.0 and 9.0, and this becauseBest et al. teach that a dramatic loss in hydrocracking performanceresults when the silica-to-alumina ratio exceeds 9.0. Specifically, whatBest et al. teach is: "Surprisingly, it has been found that when theSiO₂ to Al₂ O₃ ratio of LZ-210-T is equal to or greater than 9.0 thatthe use of LZ-210-T falls off in its hydrocracking performance. Althoughthe reasons for this markedly different performance are not known atpresent it is clear that the silica to alumina range of between greaterthan 6.0 and equal to or less than 9.0 is critical in the development ofhydrocracking catalysts based upon LZ-210-T and LZ-210-M."

The Best et al. patent application also teaches the benefits ofexchanging an LZ-210 zeolite with multivalent metals, particularly rareearth metals. The benefits disclosed are improved catalyst activity andalong life as compared to other forms of LZ-210 and as compared to Yzeolites. Another disclosed benefit is an improvement in rejuvenability.

It should be noted that neither the Breck et al. patent nor the Best etal. patent application, above cited, are to be construed as admittedprior art as to the present invention.

SUMMARY OF THE INVENTION

In the present invention it has been surprisingly found thathydrocracking catalysts comprising a hydrothermally treated andammonium-exchanged LZ-210 zeolite having a silica-to-alumina ratio above9.0 have higher catalytic activity than similar catalysts containingLZ-210 zeolite of lower silica-to-alumina ratio. Accordingly, thepresent invention is directed to a hydrocracking catalyst containing oneor more hydrogenation components selected from the Group VI and VIIImetals on a support comprising a hydrothermally treated andammonium-exchanged LZ-210 zeolite of silica-to-alumina ratio above 9.9,preferably between about 10 and 20, and most preferably from 11 to 15.

In the preferred embodiment, the catalyst is essentially free of GroupVIII noble metals and contains non-noble Group VIII metals instead. Thenon-noble Group VIII metal may be distributed upon the catalyst supportin any convenient manner, but in a preferred embodiment, the catalystcontains a novel zeolite containing the non-noble metal cation exchangedinto the LZ-210 zeolite.

In another embodiment of the invention, it has been discovered thatLZ-210 zeolites, exchanged with one or more rare earth metals, havelower activity for hydrocracking when the hydrocracking catalyst ispromoted with a non-noble Group VIII metal. Therefore, for non-noblemetal hydrocracking catalysts, it is critical in the invention that theLZ-210 zeolite be essentially free of rare earth metals, and even morepreferably, essentially free of all metals except hydrogenation metalsselected from the group consisting of Group VIB metals and nonnobleGroup VIII metals.

In yet another embodiment of the invention, it has been found that, evenfor LZ-210 zeolites having a silica-to-alumina ratio as low as 6.0, onemay obtain useful hydrocracking results with non-noble Group VIII metalspresent as a hydrogenation promoter. However, because the best resultshave been found to be obtained at a silica-to-alumina ratio above 9.0,all the preferred embodiments of the present invention employ an LZ-210zeolite of silica-to-alumina ratio above 9.0.

The following definitions pertain to the present application. The term"noble metal; refers to platinum, palladium, rhodium, iridium,ruthenium, and osmium. The term "rare earth metal" refers to lanthanum,cerium, praseodymium, neodymium, samarium, europium, gadolinium,terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.

DETAILED DESCRIPTION OF THE INVENTION

In the present invention, hydrocracking catalysts are providedcontaining as a cracking component a form of LZ-210 zeolite, andspecifically an LZ-210 zeolite having a silica-to-alumina ratio above6.0, preferably above 9.0, and more preferably from 10 to 20. Generally,LZ-210 zeolites prove unstable to thermal treatment at a SiO₂ :Al₂ O₃ratio somewhere between about 15 and 20. It is for this reason that themost preferred LZ-210 zeolites herein have a silica-to-alumina ratiofrom 10 to 15, with the most highly preferred LZ-210 zeolite having asilica-to-alumina ratio from 11 to 15.

The most preferred LZ-210 zeolites of the present invention have, in thedehydrated state, a chemical composition expressed in terms of moleratios of oxides as

    (0.85-1.1)M.sub.2/n O:Al.sub.2 O.sub.3 :xSiO.sub.2

wherein "M" is a cation having the valence "n" and "x" is a valuebetween about 10 and about 15, and most preferably between about 11 andabout 15, having extraneous silicon atoms in its crystal lattice in theform of SiO₄ tetrahedra, preferably in an average amount of at least 1.0per 10,000A³, and having an X-ray powder diffraction pattern having atleast the d-spacings set forth in the table below:

                  TABLE I                                                         ______________________________________                                        d(A)                 Intensity                                                ______________________________________                                        14.30-13.97          very strong                                              8.71-8.55            medium                                                   7.43-7.30            medium                                                   5.66-5.55            strong                                                   4.75-4.66            medium                                                   4.36-4.28            medium                                                   3.76-3.69            strong                                                   3.30-3.23            strong                                                   2.88-2.79            strong                                                   ______________________________________                                    

The Breck patent previously mentioned provides a detailed method forpreparing LZ-210 zeolites, as well as a detailed explanation of theproperties of LZ-210 zeolites (i.e., their defect structure and thelike). The preferred embodiment of the present invention requires theuse of those LZ-210 zeolites which, through appropriate treatment of a Yzeolite or the like with a fluorosilicate, have a silicate-to-aluminaratio above 9, more preferably between 10 and 20, and most preferablybetween 10 and 15. In the usual case, the preferred LZ-210 zeolite isprepared by contacting and reacting a Y zeolite of SiO₂ :Al₂ O₃ between3 and 6, and preferably an ammonium-exchanged Y zeolite of SiO₂ :Al₂ O₃between 3 and 6, at a temperature usually from 20° to 95° C. with afluorosilicate, preferably ammonium fluorosilicate, in an amount andunder conditions such that sufficient of the framework aluminum atomsare removed and replaced with silicon atoms resulting in a final SiO₂:Al₂ O₃ above 9.0. Usually, the amount of fluorosilicate and theconditions of contacting/reacting are such that at least 60 percent,preferably at least 75 percent, more preferably at least 80 percent, andmost preferably at least 90 percent, of the crystal structure of theoriginal Y zeolite is retained. After reaction is complete, the LZ-210zeolite is removed from the contacting/reacting medium, generally washedwith deionized or distilled water, and then dried, usually at atemperature between 20° and 50° C.

The LZ-210 zeolite is then stabilized by a hydrothermal treatment.Typically, the zeolite is contacted at an elevated temperature, usuallyin the range of 500° C. to the temperature at which the zeolite losessubstantial crystallinity, preferably in the range of 500° to 850° C.,with a flowing gas stream which contains sufficient water vapor toimpart a partial pressure of at least 0.2 p.s.i., preferably at least 2p.s.i., and most preferably at least 10 p.s.i. The hydrothermaltreatment (or steam calcination) is conducted for a time periodsufficient to effect some reduction in the unit cell size of thezeolite. Typically, the time for hydrothermal treatment is between 10minutes and 4 hours, preferably between 0.5 and 1.5 hours, when usingpure steam at a total pressure of 15 p.s.i.g.

Following the steam calcination, the LZ-210 zeolite is subjected to anammonium ion exchange to reduce the sodium content, typically to a valuebelow 0.5 weight percent, and preferably to below 0.2 weight percent,calculated as Na₂ O. Methods for ion exchanging zeolites with ammoniumion are well known and therefore need not be described in great detail.Usually, the exchange is accomplished with a warmed solution of anammonium salt, e.g., ammonium chloride, ammonium nitrate, ammoniumacetate, ammonium sulfate, and the like, and the exchange treatment maybe repeated with fresh solution one or more times, usually with a waterwash between exchange treatments.

Ordinarily, to achieve extremely low sodium levels in the final zeolite,it will prove necessary to repeat the ion exchange procedure at leastonce if sodium levels below about 0.05 weight percent (calculated as Na₂O) are desired. More often, the ion exchange procedure will be repeatedat least twice, and occasionally several times, before reductions insodium content below 0.05 weight percent are achieved.

After the ammonium ion exchange, the LZ-210 zeolite is separated fromthe ion exchange solution, washed free of any residual ion exchangesolution, and then heated at 100° to 200° C. for a time periodsufficient to produce a dried product. Usually, time periods of one totwo hours prove effective.

The dried zeolite product containing the ammonium cations is useful asan adsorbent, for example, in dehydrating gases containing water vapor.The zeolite product is also useful as a molecular sieve and as acatalyst for promoting hydrocarbon conversion reactions, especially withrespect to acid catalyzed hydrocarbon conversion reactions, such ascracking, alkylation, isomerization, etc., or for acid catalyzedreactions coupled with hydrogenative reactions, such as hydrocracking,hydroisomerization, and the like. For cracking, alkylation, and othernon-hydrogenative reactions, the zeolite is ordinarily dispersed in aporous refractory oxide matrix usually composed of alumina, silica,magnesia, beryllia, zirconia, titania, thoria, chromia, or combinationsthereof, such as silica-alumina, silica-zirconia, and the like. Forhydrocracking and other combined hydrogenative-acid catalyzed reactions,one or more hydrogenation components are further added, with Group VIBand VIII metals, often in combination, being utilized for this purpose.

When used for catalytic hydrocarbon conversion purposes, thehydrothermally treated and ammonium-exchanged LZ-210 zeolite is, at somepoint in the catalyst preparation procedure, calcined at an elevatedtemperature, usually in the 600° to 1600° F. range, preferably in the900° to 1500° F. range. This calcination procedure may be applied to thedried zeolite product prior to admixture with other catalytic materialsor, as is more often the case, to the zeolite when further combined inparticulate form with a precursor of the desired refractory oxide (forinstance, alumina gel in the case of alumina, silica gel in the case ofsilica, etc.), or with a salt containing one or more desiredhydrogenation metals, or with both. Calcination after admixture withother catalytic materials serves several purposes at once. In additionto converting the zeolite of the invention to a form more active foracid catalyzed hydrocarbon conversion reactions by the decomposition ofthe ammonium ions to hydrogen ions and hydroxyl groups, calcination willfurther convert the refractory oxide precursor to its desired form,e.g., gamma alumina, and the hydrogenation metal salt to thecorresponding metal oxide. Further still, the calcination hardenscatalytic materials containing refractory oxide precursors intoparticulates suitable for use in a commercial service, i.e., as a fixedor fluidized bed.

The zeolites of the present invention, although useful in a wide varietyof hydrocarbon conversion catalysts, find especial usefulness inhydrocracking catalysts. As stated hereinbefore, the typicalhydrocracking catalyst of the invention contains one or morehydrogenation metal components, a porous refractory oxide, and thezeolite of the invention. Ordinarily, the hydrogenation metal chosen isa Group VIB or VIII metal, with at least some of said Group VIII metalusually being incorporated in the zeolite by cation exchange after theammonium ion exchange or after a calcination subsequent to the ammoniumion exchange. If desired, a Group VIB metal, and particularlymolybdenum, may also be ion-exchanged into the zeolite, as for exampleby the method disclosed in U.S. Pat. No. 4,297,243, herein incorporatedby reference. More commonly, however, if a Group VIB metal is utilized,it is usually introduced after the zeolite is admixed with a refractoryoxide component, the usual procedure being to calcine the admixture,impregnate with a solution containing the Group VIB metal in an anionicform, such as ammonium heptamolybdate, and calcining again. Normally,the Group VIII metal, if a noble metal, will be introduced by cationexchange prior to admixture with the refractory oxide component, but ifa non-noble metal is chosen as the Group VIII metal, it is typicallyintroduced in cationic form into the zeolite by impregnation at a timesubsequent to admixing the zeolite and refractory oxide but prior to thefinal calcination. In this latter embodiment, it is usually the casethat the non-noble metal is introduced into the catalyst at the sametime as the Group VIB metal, usually by impregnation with an aqueoussolution containing Group VIII metal cations and the Group VIB metal inan anionic form.

One of the surprising discoveries of the present invention is that thepresence of rare earth elements in the zeolite, although taught asdesirable in the previously mentioned Best et al. European patentapplication, actually proves detrimental when the catalyst is promotedwith non-noble metal hydrogenation components. Therefore, in thepreferred embodiment of the invention as it relates to non-noble metalhydrogenation catalysts, it is critical in the present invention thatthe zeolite be essentially free of rare earth elements, and preferablyessentially free of all stabilizing polyvalent metals, and mostpreferably essentially free of all metals except non-noble metalhydrogenation metals.

Catalysts prepared in accordance with this embodiment of the inventioncontain a non-noble metal selected from the Group VIII metals,preferably nickel or cobalt, or from the Group VIB metals, such asmolybdenum, tungsten, or chromium, with molybdenum and tungstenpreferred. Most preferably in this embodiment, the catalyst containsboth a Group VIB metal and a non-noble metal Group VIII metal incombination, with the most preferred combination being nickel andtungsten. Such catalysts, as stated previously, are usually prepared byimpregnating particulates containing the zeolite mixed with a refractoryoxide, although it is also possible to admix salts of the desiredhydrogenation metal with the zeolite and a refractory oxide component,such as peptized alumina, alumina gel, or hydrated alumina, usually witha binder such as Catapal® alumina, and then providing the catalyst inparticulate form by extrusion through a die having openings of desiredsize and shape followed by breaking or cutting the extruded matter intolengths of about 1/16 to 1/2 inch. The preferred procedure differs inthat only the zeolite and refractory oxide components are extruded, withthe subsequent particulate matter then being impregnated with one ormore solutions, and most preferably only one solution, containing thedesired hydrogenation metals. In either case, however, the resultingmaterial containing the hydrogenation metal, zeolite, and refractoryoxide in particulate form is calcined at an elevated temperature,usually between about 600° and 1600° F., to produce catalytic particlesof high crushing strength.

One preferred shape for the calcined particulates is cylindrical, withcross-sectional diameters between about 1/32 and 1/8 inch. Anotherpreferred shape is that of a three-leaf clover, as shown in FIGS. 8 and8A of U.S. Pat. No. 4,028,227, herein incorporated by reference in itsentirety, with the preferred cross-sectional shape having a maximumlength D as shown in said FIG. 8A of about 1/22 inch and a lobe diameterd of about 0.28 inch. Extrusions with shapes of four lobes are alsoamong the preferred shapes.

The calcination procedure converts the hydrogenation components into theoxide form, and since hydrocracking catalysts are most active in thesulfide form, the catalyst is generally sulfided. One such method is insitu, i.e., by contact in a hydrocracking reactor with asulfur-containing feedstock under hydrocracking conditions. However, ifit is desired to presulfide the catalyst prior to use in a hydrocrackingreactor, the presulfiding can typically be accomplished by contact at anelevated temperature with a reducing gas containing hydrogen sulfide,e.g., a mix of 90 percent H₂ and 10 percent H₂ S, by volume.

Typically, the finished catalyst contains at least about 0.3 weightpercent of hydrogenation components, calculated as the metals. In theusual instance, wherein a Group VIII metal and a Group VIB metalcomponent are present in combination, the finished catalyst containsbetween about 5 and 35 percent, preferably between about 10 and 30percent by weight, calculated as the respective trioxides, of the GroupVIB metal components and between about 2 and 15 percent, preferablybetween 3 and 10 percent by weight, calculated as the respectivemonoxides, of the Group VIII metal components.

If desired, a phosphorus component may also be incorporated in thecatalyst by either comulling the support materials with phosphoric acidor including phosphoric acid in the impregnating solution. Usual andpreferred proportions of phosphorus in the catalyst fall in the rangesof 1 to 10 weight percent and 3 to 8 weight percent, calculates as P₂O₅.

Hydrocracking catalysts prepared with LZ-210 zeolite are useful in theconversion of a wide variety of hydrocarbon feedstocks to a hydrocarbonproduct of lower average boiling point and molecular weight. Thefeedstocks that may be subjected to hydrocracking by the method of theinvention include all mineral oils and synthetic oils (e.g., shale oil,tar sand products, etc.) and fractions thereof. Illustrative feedstocksinclude straight run gas oils, vacuum gas oils, and catcrackerdistillates. The typical hydrocracking feedstock, however, contains asubstantial proportion of components, usually at least 50 percent byvolume, often at least 75 percent by volume, boiling above the desiredend point of the product, which end point, in the case of gasoline, willgenerally be in the range of about 380° to 420° F. Usually, thefeedstock will also contain gas oil components boiling above 550° F.,with highly useful results being achievable with feeds containing atleast 30 percent by volume of components boiling between 600° and 1000°F.

For best results in hydrocracking, the catalyst of the invention will beemployed as a bed of catalytic particulate in a hydrocracking reactorvessel into which hydrogen and the feedstock are introduced and passedin a downwardly direction. Operating conditions in the reactor vesselare chosen so as to convert the feedstock into the desired product,which, in the preferred embodiment, is a hydrocarbon product containinga substantial proportion of gasoline components boiling, for example, inthe C₄ to 420° F. or the 185° to 420° F. range. The exact conditionsrequired in a given situation will depend upon the nature of thefeedstock, the particular catalyst composition utilized, and the desiredproduct boiling range. But in general, the conditions of operation willfall into the following suitable and preferred ranges shown in thefollowing Table II:

                  TABLE II                                                        ______________________________________                                        Conditions       Suitable  Preferred                                          ______________________________________                                        Temperature, °F.                                                                        450-850   500-800                                            Pressure, p.s.i.g.                                                                              750-3500 1000-3000                                          LHSV             0.3-5.0   0.5-3.0                                            H.sub.2 /Oil, MSCF/bbl as                                                                       1-10     2-8                                                measured at 60° F.                                                     and 1 atmosphere                                                              ______________________________________                                    

The foregoing conditions in Table II are generally correlated so as toachieve a conversion, on a crack per pass basis, of at least 40 percent,preferably at least 50 percent, and most preferably at least 60 percentby volume. The yield of C₄ to 420° F. gasoline is usually at least 50percent, preferably at least 70 percent by volume, on a once-throughbasis.

The following Examples illustrate the hydrocracking performance ofcatalysts of the invention. The examples, however, are illustrative onlyand are not intended to be construed as limiting the scope of theclaims. The scope of the invention is defined hereinafter in the claims.

EXAMPLE I

These hydrocracking catalysts were prepared and tested for theiractivity for hydrocracking against a reference catalyst. The fourcatalysts were prepared by the following procedures:

Catalyst No. 1

LZ-210 zeolite having a silica-to-alumina ratio of 6.5 washydrothermally treated by contact for 1 hour at 600° C. and 1 atmospherepressure with a flowing stream consisting essentially of pure steam. Thezeolite was then ammonium-exchanged by introducing 200 grams of thezeolite into a solution consisting essentially of 50 grams of ammoniumnitrate in 1,000 cc. deionized water for 3 hours held at a temperaturebetween about 80° and 100° C. The zeolite was then washed with deionizedwater and the ammonium exchange was repeated. This procedure reduced thesodium content of the zeolite to less than about 0.2 percent, calculatedas Na₂ O.

The zeolite was then mixed with Catapal® alumina binder such that 80percent of the mix by weight was zeolite and the remainder the alumina.The mixture was extruded through a die containing circular openings of1/16 inch diameter, broken into pieces of about 1/8 to 1/4 inch inlength, and calcined for about 1 hour at 930° F. The extrudates werethen impregnated with an aqueous solution containing about 0.2 gm/ml ofnickel nitrate (Ni₂ (NO₃)₂.6H₂ O) and 0.33 grams/ml of ammoniummetatungstate (90 percent WO₃ by weight). After removing excess liquid,the catalyst was dried at about 230° F. and, after gradual heating to930° F., was then calcined at 930° F. in flowing air for about 1 hour.The final catalyst contained about 4.4 weight percent of nickelcomponents, calculated as NiO, and about 23.0 weight percent tungstencomponents, calculated as WO₃.

Catalyst No. 2

This catalyst was prepared by the same procedure as Catalyst No. 1except that the LZ-210 zeolite had a silica-to-alumina ratio of 9.1.

Catalyst No. 3

This catalyst was prepared by the same procedure as Catalyst No. 1except that the LZ-210 zeolite had a silica-to-alumina ratio of 11.7.

The catalysts were then evaluated for hydrocracking activity in separateruns wherein a gas oil feed plus added hydrogen is passed through alaboratory-sized reactor vessel containing 150 cc. of catalyst under thefollowing conditions: 1,450 p.s.i.a., 1.7 LHSV, and a hydrogen-to-oilratio of 8,000 SCF/bbl. The gas oil feed was a denitrogenated,desulfurized, unconverted fraction obtained from a previous integralhydrofining-hydrocracking operation; it had an API gravity of 38° and aboiling range of about 360° to 870° F., with about 12 percent by volumeof the feed boiling below 400° F. To simulate hydrocracking in an H₂S-containing atmosphere, thiophene and tert-butylamine were blended withthe feedstock so as to provide respective sulfur and nitrogenconcentrations of about 0.5 and about 0.2 eight percent. The operatingtemperature utilized in the reactor vessel was adjusted periodically tomaintain a total liquid product gravity of 47° API, which, by previouslyestablished correlations, corresponds to about a 40 volume percentconversion of the feedstock to a C₄ to 420° F. gasoline product.

Each of the three catalysts was compared against a reference catalyst,which reference catalyst was a commercial hydrocracking catalyst. Thetemperature, after 100 hours of operation, at which the referencecatalyst was used to maintain the 40 percent conversion, varied somewhatin the range of about 695° to 705° F., depending upon the reactor unitin which it was run. However, for any given reactor unit, thetemperature differential between the catalyst tested therein and thereference catalyst was as follows:

                  TABLE III                                                       ______________________________________                                                   SiO.sub.2 :                                                                             Temperature Differential                                            Al.sub.2 O.sub.3                                                                        Required to Maintain 40%                                 Catalyst   Of Zeolite                                                                              Conversion                                               ______________________________________                                        No. 1      6.5        -8° F.                                           No. 2      9.1       -18° F.                                           No. 3      11.7      -23° F.                                           ______________________________________                                    

What the foregoing data indicate is that Catalyst No. 1 is 8° F. moreactive than the reference catalyst, Catalyst No. 2 18° F. more active,and Catalyst No. 3 23° F. more active. The 23° F. differentialindicates, based on previous kinetically established correlations, thatCatalyst No. 3 is roughly twice as active as the reference catalyst,i.e., if both the reference catalyst and Catalyst No. 3 were tested withall conditions except space velocity held constant, Catalyst No. 3 couldprocess twice as much feed for the same energy input (i.e., heat inputby fuel consumption) as the reference catalyst.

The data in Table III also show that the performance of otherwiseidentical Ni-W-Al₂ O₃ -LZ-210 zeolite hydrocracking catalysts is afunction of the silica-to-alumina ratio of the LZ-210 zeolite.Specifically, the catalysts having an LZ-210 zeolite ofsilica-to-alumina ratio above 9.0 had much greater activity thanCatalyst No. 1 having a silica-to-alumina ratio of only 6.5.

EXAMPLE II

This Example compares the effectiveness of Catalysts Nos. 1 and 2previously described against similar catalysts containing a rareearth-exchanged zeolite.

Catalyst No. 4

The procedure for preparing Catalyst No. 1 was repeated, except that,before the described hydrothermal treatment, the LZ-210 zeolite wascation-exchanged with a lanthanum-rich rare earth chloride solution soas to introduce rare earth cations into the zeolite.

Catalyst No. 5

The procedure for preparing Catalyst No. 2 was repeated, except that,before the described hydrothermal treatment, the LZ-210 zeolite wascation-exchanged with a lanthanum-rich rare earth chloride solutionsimilar to that described for Catalyst No. 4 under similar conditions.

When compared against the reference catalyst, by the test described inExample I, Catalyst No. 4 was found to be 3° F. less active than thereference catalyst. These data mean, based on the activities shown inTable III, that Catalyst No. 4 was 11° F. less active than Catalyst No.1--the latter differing in composition only by the absence of rareearths.

Catalyst No. 5 was found to be 5° F. more active than the referencecatalyst. But since its comparable catalyst, i.e., Catalyst No. 2, was18° F. more active than the reference catalyst, Catalyst No. 5 was 13°F. less active than Catalyst No. 2--with, again, the latter onlydiffering by the absence of rare earths.

It will also be seen, from the data just presented in this example, thatthe absence of rare earth elements even provides an advantage incatalysts containing an LZ-210 zeolite of silica-to-alumina ratio as lowas about 6.0. Thus, it is a discovery in the present invention thathydrocracking catalysts containing non-noble Group VIII metals arehighly active for hydrocracking with LZ-210 zeolites, and particularlyin the preferred embodiment wherein such zeolites are hydrothermallytreated and essentially free of cations containing rare earth metals.

Although the invention has been described in conjunction with preferredembodiments and comparative examples, it is evident that manyalternatives, modifications, and variations of the invention will beapparent to those skilled in the art in light of the foregoingdescription. For example, one may use any of a number of porousrefractory oxides in conjunction with the LZ-210 zeolite, and thepresent specification only mentions some. Another which should bementioned is the dispersion taught in U.S. Pat. No. 4,517,073, hereinincorporated by reference in its entirety, which provides for a catalystuseful in the production of both midbarrel and gasoline products.Accordingly, it is intended in the present invention to embrace all suchalternatives, modifications, and variations as fall within the spiritand scope of the appended claims.

I claim:
 1. A hydrocracking process which comprises contacting ahydrocarbon feedstock under hydrocracking conditions with hydrogen inthe presence of a hydrocracking catalyst comprising a Group VIB metalcomponent or a non-noble Group VIII metal component on a supportcomprising a zeolite aluminosilicate having a mole ratio of oxides inthe anhydrous state of

    (0.85-1.1) M.sub.2/n O:Al.sub.2 O.sub.3 :xSiO.sub.2

wherein M is a cation having a valence of "n" and "x" has a value above9.0, said aluminosilicate having an X-ray diffraction pattern comprisingat least the d-spacings set forth in Table I and having beenhydrothermally treated with resultant shrinkage in the unit cell sizefollowed by an ammonium cation exchange.
 2. A hydrocracking process asdefined in claim 1 wherein the ion exchange sites of saidaluminosilicate are essentially free of rare earth metal cations.
 3. Ahydrocracking process as defined in claim 1 wherein said aluminosilicateis essentially free of noble metals.
 4. A hydrocracking process asdefined in claim 1 wherein said hydrocracking catalyst consistsessentially of Group VIB and non-noble Group VIII metal components onsaid support.
 5. A hydrocracking process as defined in claim 4 wherein"x" has a value between about 11 and about
 15. 6. A hydrocrackingprocess as defined in claim 4 wherein said aluminosilicate, prior tosaid hydrothermal treatment, is produced by contacting a zeolite of theY crystal structure and a silica-to-alumina mole ratio below 6.0 with anaqueous fluorosilicate solution under conditions causing thesilica-to-alumina mole ratio to increase above 9.0 while retaining atleast 75 percent of the crystallinity of the zeolite prior to saidcontacting with said fluorosilicate solution.
 7. A hydrocracking processas defined in claim 1 wherein said hydrocracking catalyst comprises aGroup VIB metal component and a non-noble Group VIII metal component onsaid support.
 8. A hydrocracking process as defined in claim 7 whereinsaid Group VIB metal component comprises tungsten and said non-nobleGroup VIII metal component comprises nickel.
 9. A hydrocracking processas defined in claim 4 wherein said Group VIB metal component comprisestungsten and said non-noble Group VIII metal component comprises nickel.10. A hydrocracking process which comprises contacting a hydrocarbonfeedstock under hydrocracking conditions with hydrogen in the presenceof a hydrocracking catalyst comprising a Group VIB metal component and anon-noble Group VIII meal component on a support comprising a zeolitealuminosilicate having a mole ratio of oxides in the anhydrous state of

    (0.85-1.1) M.sub.2/n O:Al.sub.2 O.sub.3 :xSiO.sub.2

wherein M is a cation having a valence of "n" and "x" has a value above9.0, said aluminosilicate having an X-ray diffraction pattern comprisingat least the d-spacings set forth in Table I and extraneous siliconatoms in the crystal lattice in the form of framework SiO₄ tetrahedra,and said aluminosilicate having been hydrothermally treated withresultant shrinkage in the unit cell size followed by an ammonium cationexchange.
 11. A hydrocracking process as defined in claim 10 wherein theion exchange sites of said aluminosilicate are essentially free of rareearth metal cation.
 12. A hydrocracking process as defined in claim 11wherein said aluminosilicate is essentially free of noble metals.
 13. Ahydrocracking process as defined in claim 11 wherein the metalscontained in the ion exchange sites of said aluminosilicate consistessentially of metals selected from the group consisting of Group VIBand non-noble Group VIII metals.
 14. A hydrocracking process as definedin claim 11 wherein said hydrocracking catalyst consists essentially ofGroup VIB and non-noble Group VIII metal components on said support. 15.A hydrocracking process as defined in claim 14 wherein "x" has a valuebetween about 11 and about
 15. 16. A hydrocracking process as defined inclaim 10 wherein said aluminosilicate, prior to said hydrothermaltreatment, is produced by contacting a zeolite of the Y crystalstructure and a silica-to-alumina mole ratio below 6.0 with an ammoniumfluorosilicate under conditions causing the silica-to-alumina mole ratioto increase to above 9.0 while retaining at least 75 percent of thecrystallinity of the zeolite prior to said contacting with said ammoniumfluorosilicate.
 17. A hydrocracking process as defined in claim 10wherein said Group VIB metal component comprises tungsten and saidnon-noble Group VIII metal component comprises nickel.
 18. Ahydrocracking process as defined in claim 14 wherein said Group VIBmetal component comprises tungsten and said non-noble Group VIII metalcomponent comprises nickel.
 19. A hydrocracking process which comprisescontacting a hydrocarbon feedstock under hydrocracking conditions withhydrogen in the presence of a hydrocracking catalyst comprising atungsten or molybdenum component and a nickel or cobalt component on asupport comprising LZ-210 zeolite having a silica-to-alumina mole ratiogreater than about 9.0, said LZ-210 zeolite having been hydrothermallytreated with resultant shrinkage in unit cell size followed by anammonium cation exchange.
 20. A hydrocracking process as defined inclaim 19 wherein said LZ-210 zeolite has extraneous silicon atoms in thecrystal lattice in the form of framework SiO₄ tetrahedra.
 21. Ahydrocracking process as defined in claim 19 wherein the ion exchangesites of said LZ-210 zeolite are essentially free of rare earth metalcations.
 22. A hydrocracking process as defined in claim 19 wherein saidLZ-210 zeolite is essentially free of noble metals.
 23. A hydrocrackingprocess as defined in claim 19 wherein said catalyst consistsessentially of tungsten and nickel components on said support.
 24. Ahydrocracking process as defined in claim 23 wherein said LZ-210 zeolitehas a silica-to-alumina mole ratio between about 9 and about
 15. 25. Ahydrocracking process as defined in claim 19 wherein said LZ-210 zeolitehas a silica-to-alumina mole ratio between about 9.1 and about 11.7. 26.A hydrocracking process as defined in claim 8 wherein "x" has a valuebetween about 9 and about
 15. 27. A hydrocracking process as defined inclaim 8 wherein "x" has a value between about 9.1 and 11.7.
 28. Ahydrocracking process as defined in claim 26 wherein said supportfurther comprises alumina.
 29. A hydrocracking process as defined inclaim 27 wherein said support further comprises alumina.